News

Deferred Grazing

Published 15 November 12

Deferred Grazing

For the last three years Tom Mitchell, who farms on the
Wiltshire/Dorset border, has been using deferred grazing to feed
youngstock and dry cows over the winter, reducing feed and housing
costs dramatically.

"Rather than make late cuts of silage we shut up parcels of
grazing land on the perimeter of our grazing platform from the end
of August/beginning of September," explains Tom. "We keep the cows
off these areas until the middle of November then use the ground
for grazing about 40 in-calf heifers
and 60 yearlings.

"Last year one group of stock was not housed at all and we seem
to get pretty healthy, hearty cows as a result, who know how to
graze once the season starts again in spring," he says. "We do have
to worm the youngstock an extra time but the savings we make are
considerable.

"We let the cows harvest the grass where it is, greatly reducing
feed costs and housing costs such as slurry disposal. We do keep
them in three small groups in order to minimise mess so it probably
works out as having a similar labour requirement to housing the
cows, what with checking the cows and moving the fences.

"You do need to be flexible in your approach as you're never
quite sure how much land to shut up and when, as autumn grass
growth rates vary
so considerably, but shutting a bit up at a time gives you
more options."

Tom continues: "We will supplement the cows in the field if
necessary and we have the option to use sacrifice paddocks at the
end of grazing, in mid-January, or if the weather dictates. Last
year we let the weeds grow in a field of barley stubble and grazed
round bales of grass silage in-situ. The
bales were placed in the field when ground conditions were good
and then an electric fence moved over each one daily. This carried
about 30 heifers from mid-January until grazing started at the end
of March. They were never housed and seemed to thrive on the
system.

"This year we're using fields we plan to reseed as sacrifice
paddocks but the cows aren't really making a huge mess, even on our
heavy ground," he says.

"Even in December and January there is still value in the grass.
Some stores from last year, who spent the whole winter outside,
sold for 20-30% over what we usual sell at.

"When using deferred grazing I make sure we work with the slope
in fields, getting cows to graze at the top during wet weather and
at the bottom during dry periods," Tom explains. "By grazing a
square, rather than a strip, I think the cows make less mess as
they're not repeatedly pacing the same strip.

"Deferred grazing is only really an option while stocking rates
are low here (Tom milks 150 cows on a 200 acre grazing platform,
with a further 100 acres available for youngstock). As cow numbers
rise in the future we may well look to put in some winter forage
crops, but at the moment deferred grazing really does make economic
sense."

The grass Tom is using as deferred grazing was analysed and showed
the following results:

11.6ME

16.2% CP

23.5%DM.

Piers Badnell, DairyCo extension officer, comment on the
analysis and what it demonstrates to us.

"The dry matter is high and will be a reflection of the dry day
the sample was taken. This time of year, if the grass is being
grazed normally, DM would be somewhere in the top teens on dry
days, and about 15% on wet days.

"So what does this provide nutritionally? Take, for example, a
seven month, 200kg heifer, that requires 50 MJ of energy to live
and grow. On this grass, if we budget it at 11ME, the heifer
requires 4.54Kg dry matter per day to achieve this.

"We can measure and calculate this by using plate metering to
find out what entry covers and residuals are, and if we know the
area of the allocation we can calculate this dry matter figure.

"For an older animal, that can eat 3% of its body weight, the
calculation would run as follows: a 300kg animal at 3% is 9kg dry
matter per day requirement.

"Remember calculations are not real life, so monitor what you
do, how much cows are eating and of what quality (use a plate meter
and send off a grass analysis to get an accurate picture).

"Be aware that in harsh wet windy conditions they will need
extra intake, so keep an eye on conditions and how exposed the site
is.

"Monitor this growth and performance and supplement if
necessary. The deferred grazing will most likely do much more
than you expect, so question yourself before going to
concentrate, do they need it and if so how much?"